1. Field of the Invention
This invention is directed to a method and apparatus for aiding an operator in executing step-by-step procedures during the operation of a complex process facility such as a nuclear power plant. More particularly, it involves a computer based system which incorporates monitored plant data and interactive plant operator responses to recommended actions for step-by-step progression through a selected procedure and includes verification of operator responses, on-line review of completed steps, and logging of all data pertinent to procedure execution.
2. Background Information
As large process facilities become more complex, the burden placed on the operator to assimilate large amounts of data, evaluate the status of the process and various components and systems from those data, and take informed, decisive action based upon such evaluations becomes greater. Such a complex process facility where this is true is the nuclear power plant.
Due to concern for public safety and to the significance of nuclear power generation to the world, there has been steadily increasing emphasis on the need to operate nuclear power plants safely and reliably. To satisfy this need, written procedures have been developed to guide the operator in controlling the plant. However, many of these procedures are difficult for the operator to manage in a purely paper format because they require him to continuously monitor and comprehend numerous plant conditions over an extended period of time.
Several attempts have been made to alleviate this problem. One such attempt has resulted in the safety parameter display system covered by U.S. Pat. No. 4,552,718. This system generates meaningful information for the operator of a pressurized water reactor (PWR) on six critical safety functions which must be maintained, or reestablished if lost, during emergency operation. The system uses a status tree approach to generate automatically, or through manual responses by an operator, a visual indication of the current status of all six critical safety functions. This system is used in conjunction with the paper procedures t alert the operator, who is absorbed in the steps of a particular emergency procedure, to the overall condition of the plant. While the status tree system advises the operator of any threats to the critical safety functions, and suggests a procedure to be followed, the operator must still locate the recommended procedure in the paper procedures and then follow it manually step-by-step. The status tree system also does not keep the operator apprised of other plant conditions which the paper procedures require be monitored, but which do not directly affect the critical safety functions.
U.S. patent application Ser. No. 825,427 filed on Feb. 3, 1986, and referred to above under the heading, Related Application, is directed to a computer based system which both assesses the plant data and provides guidance in light of predefined procedures. In this system, current plant data are used by the computer to trace a path through the logic of appropriate procedure steps in order to identify a recommended course of action. The course of action along, with related data, is displayed for the operator on one or more electronic display devices. The computer then uses the plant data and the operator's interactive response to proceed to the next appropriate procedure step. In addition, the computer simultaneously monitors certain functions which must normally be continuously monitored by the operator. If a problem becomes apparent in any of these functions, the operator is alerted and appropriate actions are displayed. In this manner, the operator is relieved of the duty of continually gathering and assessing large amounts of data, as required by the purely paper form of the procedures. This frees the operator to concentrate on operating the plant in a safe manner when hazardous conditions are not present, and to alleviate potential emergency situations when hazardous conditions exist.
Although this computer based system performs its intended function, development and testing uncovered some areas where improvements in performance of the system could be made.
Hence, it is the primary object of the subject invention to provide improved apparatus and method for a computer based system for assisting the operator of a complex process facility in carrying out step-by-step procedures.
It is a more specific object of the invention to provide such an apparatus and method in which the operator maintains control of procedure implementation, but in which progression cannot be made to the next step until an action taken by the operator has been verified by the plant sensors, or until the operator overrides the system.
It is another object of the invention to provide such an apparatus and method which assists the operator in detecting malfunctioning equipment.
It is still another object of the invention to provide such an apparatus and method which permits on-line review of prior steps without interrupting execution of the current step.
Yet another object of the invention is to provide such an apparatus and method with improved logging capability.